Arsenal manager Arsene Wenger hopes that midfielder Jack Wilshere will be back in action within a month.
The 20-year-old England international had ankle surgery in September before suffering a stress fracture in his right foot during his recovery.
"Jack can be back within a month if all goes well," said Wenger.
However, Arsenal expect to be without Per Mertesacker for a month after the German defender was carried off against Sunderland with an ankle injury.
Wilshere has not played this season, having picked up the original injury, later diagnosed as a stress fracture to his right ankle, in a pre-season friendly against New York Red Bulls on 31 July.
Wenger is keen to take a more careful approach to the England midfielder's return after Wilshere picked up his latest injury while undergoing his rehabilitation.
"The recovery of his latest problems looks very good," added Wenger. "The latest scan was very positive.
"We go cautiously step by step because we tried to push him back quicker in the first instance and he had a setback. So this time we have to be cautious and not go too quick.
"He can be back before then end of the season, of course."
However, Wenger is less positive about the return of Mertesacker, who injured his ankle as he attempted to control the ball in the move that led to Sunderland's goal in Saturday's 2-1 win at the Stadium of Light.
The 27-year-old has returned to Germany to have his ankle assessed.
"He had a reconstruction of his ankle in Germany before he joined us," added Wenger. "And the scan didn't look to positive yesterday.
"He went back to Germany to consult the specialist to see where we go from there and he is supposed to contact me this afternoon to tell me exactly what the specialist told him.
"Certainly in the next month he will not be with us."